Cylinder head arrangements for internal combustion engines



Sept. 17, 1963 H. SEIFERT ETAL 3,103,921

CYLINDER HEAD ARRANGEMENTS FOR INTERNAL COMBUSTION ENGINES Filed July28, 1961 2 Sheets-Sheet 1 Sept. 17, 1963 H. SEIFERT ETAL 3,103,921

CYLINDER HEAD ARRANGEMENTS FOR INTERNAL COMBUSTION ENGINES Filed July28. 1 961 2 Sheets-Sheet 2 United States Patent Ofi 3,103,921 PatentedSept. 17, 1963 ice 3,103,921 CYLINDER HEAD ARRANGEMENTS FOR INTERNALCOMBUSTION ENGINES Hans Seifert and Karl-Heinz Hoseus, Mannheim,Germany, assignors to Motoren-Werke Mannheim AG. vorm. Benz Abt. stat.Motorenbau, Mannheim, Germany, a German company Filed July 28, 1961,Ser. No. 127,574 Claims priority, application Germany Aug. 11, 1960 6Claims. (Cl. 123-32) This invention relates to cylinder headarrangements for internal combustion engines. It is known to detachablymount the bodies of auxiliary combustion chambers on air-cooled,light-metal cylinder heads by means of fixing bolts which press the bodyonto the outer end face of a heavy metal ring let into a base plate ofthe cylinder head, the base plate forming an end of the cylinder spacewith which the auxiliary combustion chamber communicates via one or moretransfer orifices.

In such a method of fixing, the mounting of the fixing bolts in thecylinder head offers considerable difliculties, since in operation thestrength of the light metal in the region of the base plate near thetransfer orifices and at the web between the valves, i.e. in thevicinity at which the fixing bolts must necessarily be screwed, is verylow, due to the concentrated heat generation at these plates. Hence inthe event of powerful tightening, the bolts are torn out of the lightmetal. This drawback may be obviated if the fixing bolts are screwedinto parts of the cylinder head which are sufliciently remote from thehighly heated places. In this known construction, however, a newdrawback arises which is that the part of the base plate at which thecombustion chamber body is applied, yields in a kind of creep processdue to the continuous pressure of application and bulges towards thecylinder interior, so that the piston strikes against this part of thebase plate.

According to the present invention there is provided a cylinder headarrangement for an internal combustion engine, comprising an air-cooledcylinder head that includes a base plate, an auxiliary combustionchamber body, there being an orifice for placing the chamber of saidbody in communication with a cylinder space of said engine, a yoke fixedin the cylinder head and including a ring supporting said body and armsextending outwardly from said ring, and fixing bolts detachably securingsaid body to said head, the bolts being screwed into said arms andurging said body against said ring.

In the temperature range coming into consideration the arrangementprovided is practically thermally insensitive and is therefiore capableof supporting in continuous operation the stresses occurring.

A particular resistant construction of the supporting arms is obtainedif the heavy metal ring terminates in, or at least approximately in, theplane of the surface of the base plate confining the cylinder space andif reinforcing and connecting ribs extend from the ring along said arms.

Leakages are obviated by the supporting arms having sleeves at theextremities thereof, into which sleeves the fixing bolts are screwed andwhich are completely surrounded by the light metal of the cylinder head.

Advantageously, the cylinder head is provided with projections againstwhich the cylindrical parts of the supporting arms are pressed under theinfluence of the excess pressure prevailing in the cylinder space.

A connection, adequate for the present purpose, of the heavy metal ringand supporting arms with the light metal of the cylinder head can beobtained by the surface of the heavy metal ring and supporting armshaving a roughness as normally produced by casting or forging.

For a better understanding of the invention and to show how the same maybe carried into effect, reference will now be made, by way of example,to the figures of the accompanying drawings, in which:

FIGURE 1 is a section through a cylinder head arrangement, the sectionbeing taken on the line 1--1 0f FIGURE 2,

FIGURE 2 is a section on the line 22 of FIGURE 1 and,

FIGURE '3 is a top plan view of the internal ing yoke.

As shown in FIGURES 1 and 2 of the drawings an internal retaining yoke2, consisting of a heavy metal ring 3 and supporting arms 4, is cast ina light-metal aireooled cylinder head 1. The two supporting arms 4respectively comprise a rib 6 and a sleeve or cylindrical part 5, and arib 7 and a part 5. The parts 5 are connected to the ring 3 by the ribs6 and 7 which serve as reinforcing ribs. The free end of the ring 3terminates in the plane of a surface S of a base plate 9 which confinesthe cylinder space. Fixing bolts 10 are screwed into bores in the parts5. The bolts 10 press an insert 11 on to the ring 3, the pressing forcebeing transmitted from nuts 12 via spring packs 13, spherical washers14, an external yoke 15, an auxiliary combustion chamber body 16 andpacking rings 17 and 18. A transfer orifice 19 is situated in the insert11, the insert 11 and the internal yoke 2 preferably being ofheat-resistant steel. 20 indicates a threaded bore for the reception ofan injection nozzle (not shown), which injects fuel into the pre-chamber21. A threaded bore 24 formed in the chamber body 16 receives a glowplug (not shown) for the starting of the engine. The internal yoke 2 iscast or forged and has the rough surface which is produced by suchmanufacturing processes. The spring packs 13 serve to equalize thedifferent thermal expansions of the auxiliary combustion chamber body 16and the bolts 10. In order that the combustion pressure in the cylinderspace acting on that surface of the ring 3 which lies in the plane ofthe surface 8 may not break loose the bond between the yoke 2 and thesurrounding light metal of the cylinder head 1, parts 5 of the yoke 2are so arranged as to bear against the lower flat surfaces of theprojections 22.

We claim:

1. A cylinder head arrangement for an internal combustion engine,comprising an air-cooled cylinder head that includes a base plate, anauxiliary combustion chamber body, there being an orifice for placingthe chamber of said body in communication with a cylinder space of saidengine, a yoke fixed in the cylinder head and including a ringsupporting said body and arms extending outwardly from said ring, andfixing bolts detachably securing said body to said head, the bolts beingscrewed into said arms and urging said body against said ring.

2. A cylinder head arrangement according to claim 1, wherein said armshave at the outer extremities thereof internally threaded sleeves forreceiving said bolts, said sleeves being surrounded by the metal of thecylinder head.

3. A cylinder head arrangement for an internal combustion engine,comprising an air-cooled cylinder head that includes a base plate, anauxiliary combustion chamber body, there being an orifice for placingthe chamber of said body in communication with a cylinder space of saidengine, a yoke fixed in the cylinder head and including a ring and armswhich extend outwardly from said ring, said ring being entered in anaperture in said base plate and supporting said body, an end surface tosaid ring, said end surface being approximately in the plane of thatsurface of said base plate which is remote from said body, and fixingbolts detachably securing said retainbody to said head, said bolts beingscrewed into said arms and urging said body against said ring.

4. A cylinder head arrangement according to claim 3, wherein said armshave at the outer extremities thereof internally threaded sleeves forreceiving said bolts, and wherein there are projections on said cylinderhead against which projections the sleeves are urged by the combustiongases in said space.

5. A cylinder head arrangement according to claim 4, wherein saidprojections extend inwardly from an interior wall of said head, saidbolts passing through said projections.

6. A cylinder head arrangement for an internal combustion engine,comprising an air-cooled cylinder head that includes a base plate, 'anauxiliary combustion chamher body, there being an orifice for placingthe chamber of said body in communication with a cylinder space of saidengine, a first yoke fixed in the cylinder head and including a ringsupporting said body and arms extending outwardly from said ring, asecond yoke having apertured end portions and a central portionco-operating with said body, and fixing bolts passed through saidapentured end portions and secured in said arms to cause said centralportion to urge said body against said ring.

References Cited in the file of this patent UNITED STATES PATENTS2,985,155 Hockel May 23, 1961

1. A CYLINDER HEAD ARRANGEMENT FOR AN INTERNAL COMBUSTION ENGINE,COMPRISING AN AIR-COOLED CYLINDER HEAD THAT INCLUDES A BASE PLATE, ANAUXILIARY COMBUSTION CHAMBER BODY, THERE BEING AN ORIFICE FOR PLACINGTHE CHAMBER OF SAID BODY IN COMMUNICATION WITH A CYLINDER SPACE OF SAIDENGINE, A YOKE FIXED IN THE CYLINDER HEAD AND INCLUDING A RINGSUPPORTING SAID BODY AND ARMS EXTENDING OUTWARDLY FROM SAID RING, ANDFIXING BOLTS DETACHABLY SECURING SAID BODY TO SAID HEAD, THE BOLTS BEINGSCREWED INTO SAID ARMS AND URGING SAID BODY AGAINST SAID RING.